The Illinois High School Association has a complex rating formula (see below). For the most part I believe it is a fair system.
Ratings Explanation
How the Ratings Percentile is Determined: All ratings in a particular sport that are received during the current school term, plus the two previous school terms, are averaged and then divided by the number of ratings. The result is that an official who works often (and is rated often) will generally receive a better ranking than an official who obtains a high average on just a handful of ratings. These numbers are sorted from top to bottom and divided into 100 groups of equal size. The officials in the highest group are assigned to the 99th percentile, the next group to the 98th, and so on down to 0.
Why Your Rating Percentile Suddenly Went Down (Probably): At the start of the new school term, the ratings from three years ago are no longer included when computing your percentile. If you had a lot of good ratings three years ago, or if you simply had a lot of ratings three years ago, your percentile is likely to go down when the new rating is computed.
How the Top 15 Percentile is Determined: All Top 15 Lists in a particular sport that have been updated during the last two years (730 days) are used. Officials receive points based on their position in the lists: 15 points for each 1st-place mention, 14 points for each 2nd-place mention, and so on down to 1 point for each 15th-place mention. The total points are sorted from top to bottom and divided into 100 groups of equal size. The officials in the highest group are assigned to the 99th percentile, the next group to the 98th, and so on down to 0.
Why Your Top 15 Percentile Suddenly Went Down (Probably): Top 15 Lists expire exactly two years (730 days) after they were submitted. If you are at or near the top of a list that recently expired, your percentile is likely to go down when the new rating is computed.
Alternatively, you may recently have been moved down in the rankings (or completely removed from the rankings) on a Top 15 list or lists. Such a change can often result is a fairly dramatic drop in your percentile.
Power Rating Explanation
About the Power Rating (listed on main page): The Power Rating is calculated on or about the "snapshot date" of September 7 for fall sports. Any information that changes after the snapshot date -- including clinic attendance, change in promotion level, or ratings by schools or officials -- will not be included in the Power Rating. The IHSA administrator uses the Power Rating calculated on the snapshot date to make state series assignments. The Power Rating is viewable for two months after the snapshot date.
How the Power Rating is Determined: The power rating is a number from 0 to 40, derived from 8 different criteria, as follows:
Promotion level: Certified (C) -- 5 pts., Recognized (R) -- 3 pts., Registered (X) -- 1 pt.
Part 1 exam score: 96 -- 5 pts., 92 -- 4 pts., 88 -- 3 pts., 84 -- 2 pts, 80 -- 1 pt.
Previous tournament experience for contests by this gender: state final -- 5 pts., super-sectional or football semifinal -- 4 pts., sectional or football quarterfinal -- 3 pts., football second-round game -- 2 pts., regional or other football playoff game -- 1 pt.
Contest ratings (percentile rank of all officials): 90% -- 5 pts., 80% -- 4 pts., 70% -- 3 pts., 60% -- 2 pts., 50% -- 1 pt.
Top 15 lists (percentile rank of all officials): 90% -- 5 pts., 80% -- 4 pts., 70% -- 3 pts. 60% -- 2 pts., 50% -- 1 pt.
Clinic attendance (highest clinic in last three years): Level 2 -- 5 pts., Level 1 -- 2 pts., Level 0 -- 0 pts.
Clinic attendance (most recent clinic): this year -- 5 pts., last year -- 3 pts., two years ago -- 1 pt.
Varsity games worked (percentage of games a school is allowed to play in the regular season in that sport): 70% -- 5 pts., 60% -- 4 pts., 50% -- 3 pts., 40% -- 2 pts., 30% -- 1 pt. See table below.
5 pts. 4 pts. 3 pts. 2 pts. 1 pt.
SPORT MAX 70% 60% 50% 40% 30%
Football 9 7 6 5 4 3
MAX = number of contests (outside of tournaments) allowed per school by IHSA by-laws